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package org.openjdk.jmh.samples;


import org.openjdk.jmh.annotations.Benchmark;

import org.openjdk.jmh.annotations.BenchmarkMode;

import org.openjdk.jmh.annotations.CompilerControl;

import org.openjdk.jmh.annotations.Mode;

import org.openjdk.jmh.annotations.OutputTimeUnit;

import org.openjdk.jmh.annotations.Scope;

import org.openjdk.jmh.annotations.State;

import org.openjdk.jmh.runner.Runner;

import org.openjdk.jmh.runner.RunnerException;

import org.openjdk.jmh.runner.options.Options;

import org.openjdk.jmh.runner.options.OptionsBuilder;

import org.openjdk.jmh.runner.options.WarmupMode;


import java.util.concurrent.TimeUnit;


@State(Scope.Thread)

@BenchmarkMode(Mode.AverageTime)

@OutputTimeUnit(TimeUnit.NANOSECONDS)

public class JMHSample_32_BulkWarmup {


 /*

  * This is an addendum to JMHSample_12_Forking test.

  *

  * Sometimes you want an opposite configuration: instead of separating the profiles

  * for different benchmarks, you want to mix them together to test the worst-case

  * scenario.

  *

  * JMH has a bulk warmup feature for that: it does the warmups for all the tests

  * first, and then measures them. JMH still forks the JVM for each test, but once the

  * new JVM has started, all the warmups are being run there, before running the

  * measurement. This helps to dodge the type profile skews, as each test is still

  * executed in a different JVM, and we only "mix" the warmup code we want.

  */


 /*

  * These test classes are borrowed verbatim from JMHSample_12_Forking.

  */


 public interface Counter {

  int inc();

 }


 public static class Counter1 implements Counter {

  private int x;


  @Override

  public int inc() {

   return x++;

  }

 }


 public static class Counter2 implements Counter {

  private int x;


  @Override

  public int inc() {

   return x++;

  }

 }


 Counter c1 = new Counter1();

 Counter c2 = new Counter2();


 /*

  * And this is our test payload. Notice we have to break the inlining of the payload,

  * so that in could not be inlined in either measure_c1() or measure_c2() below, and

  * specialized for that only call.

  */


 @CompilerControl(CompilerControl.Mode.DONT_INLINE)

 public int measure(Counter c) {

  int s = 0;

  for (int i = 0; i < 10; i++) {

   s += c.inc();

  }

  return s;

 }


 @Benchmark

 public int measure_c1() {

  return measure(c1);

 }


 @Benchmark

 public int measure_c2() {

  return measure(c2);

 }


 /*

  * ============================== HOW TO RUN THIS TEST: ====================================

  *

  * Note how JMH runs the warmups first, and only then a given test. Note how JMH re-warmups

  * the JVM for each test. The scores for C1 and C2 cases are equally bad, compare them to

  * the scores from JMHSample_12_Forking.

  *

  * You can run this test:

  *

  * a) Via the command line:

  *    $ mvn clean install

  *    $ java -jar target/benchmarks.jar JMHSample_32 -f 1 -wm BULK

  *    (we requested a single fork, and bulk warmup mode; there are also other options, see -h)

  *

  * b) Via the Java API:

  *    (see the JMH homepage for possible caveats when running from IDE:

  *      http://openjdk.java.net/projects/code-tools/jmh/)

  */


 public static void main(String[] args) throws RunnerException {

  Options opt = new OptionsBuilder()

          .include(JMHSample_32_BulkWarmup.class.getSimpleName())

          // .includeWarmup(...) <-- this may include other benchmarks into warmup

          .warmupMode(WarmupMode.BULK) // see other WarmupMode.* as well

          .forks(1)

          .build();


  new Runner(opt).run();

 }
// 本例介绍了三种预热方式：
//
// WarmupMode.INDI：每个Benchmark单独预热
// WarmupMode.BULK：在每个Benchmark执行前都预热所有的
// BenchmarkWarmupMode.BULK_INDI：在每个Benchmark执行前都预热所有的Benchmark，且需要再预热本次执行的Benchmark

}